1. Field of the Invention
The present invention relates to a vehicular headlamp that is capable of adjusting an optical axis with use of an aiming mechanism and a leveling actuator.
2. Description of Related Art
A vehicular headlamp include the type in which a lamp unit including a lamp source is accommodated inside a lamp outer case that is constituted by a cover and a lamp housing, the lamp unit is rotatably (tiltably) supported by an aiming mechanism via a supporting member such as a bracket, and the lamp unit is allowed to rotate by a driving force of a levelling actuator (See, for example, Japanese Patent Application Publication No. 2008-300363 (JP 2008-300363 A), for example).
In such a vehicular headlamp, the aiming mechanism rotates the lamp unit to move in a vertical or lateral direction and so-called “aiming adjustment” for initial adjustment of an optical axis offset is thereby performed, while the leveling actuator rotates the lamp unit to move in the vertical direction and so-called “leveling adjustment” for adjusting an optical axis offset which varies depending on a load on a vehicle
In the vehicular headlamp disclosed in JP 2008-300363 A, a pair of laterally spaced aiming shafts are provided at an upper end portion of a bracket that supports the lamp unit. In addition, an output shaft of the leveling actuator is connected to the bracket at a position directly under a portion to which one of the aiming shafts is connected. Thus, the connected positions of the aiming shafts to the bracket and the connected position of the leveling actuator forms an L-shaped connecting state.
However, in the vehicular headlamp disclosed in JP 2008-300363 A, the L-shaped connecting state formed by the connected positions of the aiming shafts to the bracket and the connected position of the leveling actuator may reduce the balance between the connected positions relative to the lamp unit. Accordingly, it is difficult to secure sufficient strength of the vehicular headlamp against vibrations.
In addition, the output shaft of the leveling actuator is arranged at a position offset to the right or the left from the central axis of the lamp unit and thus the leveling actuator tends to be arranged in a lopsided state. As a result, it is difficult to efficiently utilize the internal space of a lamp outer case and may prevent size reduction of the vehicular headlamp.